Adiabatic adsorption, in a mode known as "pressure-swing adsorption" is widely used for gas purification and separation because the desorption/regeneration phase does not require thermal energy but instead is effected by a pressure relief following the adsorption phase.
Thus it is known to provide a system or method for adiabatic adsorption in which a plurality of switchable adsorbers are cycled between an adsorption stage and a regeneration or desorption stage which can include at least two pressure-relief stages followed by a pressure-buildup stage and with intervening purging.
In such systems, the gases released by the pressure relief of the adsorption medium from one adsorber can be used for pressure equalization or pressure buildup in another adsorber.
The more adsorbers included in the system, the more pressure relief and pressure buildup stages are provided.
The advantages of such systems include better utilization of the pressure-relief gases, i.e. the gases remaining in the voids of the gas-permeable adsorption medium after conclusion of the adsorption phase.
Notwithstanding the numerous techniques which have utilized the pressure swing approach and the large number of systems which have been developed based thereon, it has been found that the economy of the system still leaves much to be desired and that there is not always an optimum utilization of the apparatus.